The present invention relates to a circuit module and a manufacturing method thereof, and more specifically, to a circuit module including an underfill at a solder joint section of a substrate and a semiconductor chip, and a manufacturing method thereof.
In the semiconductor packaging technology, highly reliable connection between a semiconductor chip and an organic substrate is made difficult by miniaturization of bumps and weakening of a wiring layer caused by lowered K of a dielectric layer. Generation of a great internal stress caused by different temperature deformations due to the CTE difference between Si (coefficient of thermal expansion (CTE): ˜4 ppm) and an organic substrate material (adjusted according to a copper wiring to achieve CTE of about 17 ppm) may be cited as a cause. A fine BEOL or a bump joint may be destroyed by this stress.
Accordingly, strengthening of the structure is performed by injecting an underfill at a bump joint section of a substrate and a semiconductor chip and by hardening the underfill. In this case, a pre-coating method (also referred to as a “no-flow underfill” method) of realizing bump connection in a state where resin is applied in advance on the joining surface may be used (for example, Patent Document 1). This method is gaining attention as a method that is capable of simplifying a process, of reducing the processing time of narrow-gap joining, and of reducing the temperature variation during a process.
However, in the case of using a conventional pre-coating method, a fillet cannot be formed because a sufficient amount of underfill resin is not supplied to corner portions of a semiconductor chip, and this is known to lead to destruction of the joining section. FIG. 1 illustrates an example where an underfill is formed by a conventional pre-coating method. A top view is illustrated in (a), and a side view is illustrated in (b). In the case where a semiconductor chip 91 on which resin is applied in advance is joined to a substrate 90, a sufficient amount of resin is not supplied to corner portions 93 of the semiconductor chip 91, and appropriate fillets (underfills) 92 are not formed at especially the corner portions 93 and their peripheries. In order to prevent this, a method of further applying resin on the corner portions after joining by the pre-coating method is taken, for example, but this increases the number of processes and complicates the processes.